Japanese encephalitis virus genotype III from mosquitoes in Tarlac, Philippines

Aure, Wilfredo E.; Sayama, Yusuke; Saito-Obata, Mariko; Salazar, Nelia P.; Malbas, Fedelino I.; Galang, Hazel; Imamura, Tadatsugu; Lopez, Cecil; Oshitani, Hitoshi

doi:10.1016/j.ijregi.2022.05.005

Cited by 7 publications

(3 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…JEV was rst isolated from mosquitoes in 1977 and in the 1980s in the Philippines [16-19] Evidence of human infection was derived mainly from serologic surveys and clinical reports [14]. Kuwata's surveillance of JEV in mosquitoes and pigs in Southeast Asia was followed by Aure's nding of JEV GIII from mosquitoes in San Jose [21,22]. In this present study JEV GIII was detected from serum and nasal swabs in pigs (Fig.…”

Section: Resultsmentioning

confidence: 63%

“…The presence of IgM and IgG antibodies in young and older pigs during all four observation periods in 2010-2011 indicated year-round transmission starting with the rainy season which encompasses the months of July and September. Aure reported rainfall and mosquito populations starting to peak in July 2010 [21]. Water is essential for wet rice-cultivation and for vector mosquito development.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Japanese Encephalitis in Swine in San Jose, Tarlac, Philippines

Malbas,

Saito-Obata,

Sayama

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

Background A systematic review of multidisciplinary studies on Japanese encephalitis (JE) in the Philippines indicated that endemic foci may be found in all 17 administrative regions in the country. To establish the etiology of the disease virus isolation and seroprevalence surveys in 198 pigs were conducted in 2010–2011 in four barangays (villages) in the Municipality of San Jose, Tarlac. Prior to this present study Japanese encephalitis virus genotype III (JEV GIII) was recovered from the mosquito, Culex tritaeniorhynchus in the same municipality where backyard hog-raising and wet rice-cultivation were common practices among households located within one kilometer radius from paddies. Results JEV GIII was detected from serum and nasal swabs from pigs, 3–5 months old, from barangays Pao, Moriones and Villa Aglipay. IgM and IgG were measured by ELISA in pigs less than 4 to more than 8 months old, with an overall total of 17.2% and 62.1%, respectively. The presence of these antibodies in all pigs during four observation periods indicated year-round transmission starting with the rainy season which encompasses the months of July and September 2010. IgG increased correspondingly with age with repeated infections in older pigs. IgG prevalence rates remained high in all barangays. The proportions of positive households with any one of the markers: IgM, IgG, RT-PCR were above 80% or an average of 82.5% of households where all pigs were examined. This report contributes to knowledge on JE where incidence in humans may be linked to its epizootic spillover from pigs. Conclusion The study has shown that four barangays, representing a rice-farming community, supported the enzootic cycle of JE in swine, with mosquitoes previously found to be infected with JEV GIII, in San Jose. Thus, infected pigs, rainfall and proximity of human habitation to breeding sites of vector mosquitoes constituted the risk factors for JE as it were in other endemic countries in Asia. The finding of viral RNA in nasal swabs suggests the possibility of direct transmission among pigs via oronasal route. From the standpoint of public health JE immunization of children and periodic surveillance in swine are recommended.

show abstract

Section: Resultsmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Japanese Encephalitis in Swine in San Jose, Tarlac, Philippines

Malbas,

Saito-Obata,

Sayama

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, JEV cases have been controlled to a significant extent by the use of JEV vaccines all over Asian countries [ 7 ], and the demographic history of JEV has been reported in previous studies [ 2 , 8 , 9 ]. However, due to the continued spread of JEV to non-endemic areas such as Tibet, Xinjiang, Philippines, and Australia [ 10 , 11 , 12 , 13 , 14 ] and continuous detection from mosquitoes or vertebrate hosts of endemic regions [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ], we felt that there is a need to reconstruct the molecular phylogeny and population dynamics of JEV using recent isolates (till December 2022) of JEV for the future perception of disease spread.…”

Section: Introductionmentioning

confidence: 99%

Recent Population Dynamics of Japanese Encephalitis Virus

Wahaab

Khan

et al. 2023

Viruses

View full text Add to dashboard Cite

Japanese encephalitis virus (JEV) causes acute viral encephalitis in humans and reproductive disorders in pigs. JEV emerged during the 1870s in Japan, and since that time, JEV has been transmitted exclusively throughout Asia, according to known reporting and sequencing records. A recent JEV outbreak occurred in Australia, affecting commercial piggeries across different temperate southern Australian states, and causing confirmed infections in humans. A total of 47 human cases and 7 deaths were reported. The recent evolving situation of JEV needs to be reported due to its continuous circulation in endemic regions and spread to non-endemics areas. Here, we reconstructed the phylogeny and population dynamics of JEV using recent JEV isolates for the future perception of disease spread. Phylogenetic analysis shows the most recent common ancestor occurred about 2993 years ago (YA) (95% Highest posterior density (HPD), 2433 to 3569). Our results of the Bayesian skyline plot (BSP) demonstrates that JEV demography lacks fluctuations for the last two decades, but it shows that JEV genetic diversity has increased during the last ten years. This indicates the potential JEV replication in the reservoir host, which is helping it to maintain its genetic diversity and to continue its dispersal into non-endemic areas. The continuous spread in Asia and recent detection from Australia further support these findings. Therefore, an enhanced surveillance system is needed along with precautionary measures such as regular vaccination and mosquito control to avoid future JEV outbreaks.

show abstract